git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/bset.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Code for working with individual keys, and sorted sets of keys with in a
   4  * btree node
   5  *
   6  * Copyright 2012 Google, Inc.
   7  */
   8
   9 #include "bcachefs.h"
  10 #include "btree_cache.h"
  11 #include "bset.h"
  12 #include "eytzinger.h"
  13 #include "util.h"
  14
  15 #include <asm/unaligned.h>
  16 #include <linux/console.h>
  17 #include <linux/random.h>
  18 #include <linux/prefetch.h>
  19
  20 /* hack.. */
  21 #include "alloc_types.h"
  22 #include <trace/events/bcachefs.h>
  23
  24 static inline void __bch2_btree_node_iter_advance(struct btree_node_iter *,
  25                                                   struct btree *);
  26
  27 static inline unsigned __btree_node_iter_used(struct btree_node_iter *iter)
  28 {
  29         unsigned n = ARRAY_SIZE(iter->data);
  30
  31         while (n && __btree_node_iter_set_end(iter, n - 1))
  32                 --n;
  33
  34         return n;
  35 }
  36
  37 struct bset_tree *bch2_bkey_to_bset(struct btree *b, struct bkey_packed *k)
  38 {
  39         unsigned offset = __btree_node_key_to_offset(b, k);
  40         struct bset_tree *t;
  41
  42         for_each_bset(b, t)
  43                 if (offset <= t->end_offset) {
  44                         EBUG_ON(offset < btree_bkey_first_offset(t));
  45                         return t;
  46                 }
  47
  48         BUG();
  49 }
  50
  51 /*
  52  * There are never duplicate live keys in the btree - but including keys that
  53  * have been flagged as deleted (and will be cleaned up later) we _will_ see
  54  * duplicates.
  55  *
  56  * Thus the sort order is: usual key comparison first, but for keys that compare
  57  * equal the deleted key(s) come first, and the (at most one) live version comes
  58  * last.
  59  *
  60  * The main reason for this is insertion: to handle overwrites, we first iterate
  61  * over keys that compare equal to our insert key, and then insert immediately
  62  * prior to the first key greater than the key we're inserting - our insert
  63  * position will be after all keys that compare equal to our insert key, which
  64  * by the time we actually do the insert will all be deleted.
  65  */
  66
  67 void bch2_dump_bset(struct bch_fs *c, struct btree *b,
  68                     struct bset *i, unsigned set)
  69 {
  70         struct bkey_packed *_k, *_n;
  71         struct bkey uk, n;
  72         struct bkey_s_c k;
  73         char buf[200];
  74
  75         if (!i->u64s)
  76                 return;
  77
  78         for (_k = i->start;
  79              _k < vstruct_last(i);
  80              _k = _n) {
  81                 _n = bkey_next(_k);
  82
  83                 k = bkey_disassemble(b, _k, &uk);
  84                 if (c)
  85                         bch2_bkey_val_to_text(&PBUF(buf), c, k);
  86                 else
  87                         bch2_bkey_to_text(&PBUF(buf), k.k);
  88                 printk(KERN_ERR "block %u key %5zu: %s\n", set,
  89                        _k->_data - i->_data, buf);
  90
  91                 if (_n == vstruct_last(i))
  92                         continue;
  93
  94                 n = bkey_unpack_key(b, _n);
  95
  96                 if (bpos_cmp(n.p, k.k->p) < 0) {
  97                         printk(KERN_ERR "Key skipped backwards\n");
  98                         continue;
  99                 }
 100
 101                 if (!bkey_deleted(k.k) &&
 102                     !bpos_cmp(n.p, k.k->p))
 103                         printk(KERN_ERR "Duplicate keys\n");
 104         }
 105 }
 106
 107 void bch2_dump_btree_node(struct bch_fs *c, struct btree *b)
 108 {
 109         struct bset_tree *t;
 110
 111         console_lock();
 112         for_each_bset(b, t)
 113                 bch2_dump_bset(c, b, bset(b, t), t - b->set);
 114         console_unlock();
 115 }
 116
 117 void bch2_dump_btree_node_iter(struct btree *b,
 118                               struct btree_node_iter *iter)
 119 {
 120         struct btree_node_iter_set *set;
 121
 122         printk(KERN_ERR "btree node iter with %u/%u sets:\n",
 123                __btree_node_iter_used(iter), b->nsets);
 124
 125         btree_node_iter_for_each(iter, set) {
 126                 struct bkey_packed *k = __btree_node_offset_to_key(b, set->k);
 127                 struct bset_tree *t = bch2_bkey_to_bset(b, k);
 128                 struct bkey uk = bkey_unpack_key(b, k);
 129                 char buf[100];
 130
 131                 bch2_bkey_to_text(&PBUF(buf), &uk);
 132                 printk(KERN_ERR "set %zu key %u: %s\n",
 133                        t - b->set, set->k, buf);
 134         }
 135 }
 136
 137 #ifdef CONFIG_BCACHEFS_DEBUG
 138
 139 void __bch2_verify_btree_nr_keys(struct btree *b)
 140 {
 141         struct bset_tree *t;
 142         struct bkey_packed *k;
 143         struct btree_nr_keys nr = { 0 };
 144
 145         for_each_bset(b, t)
 146                 bset_tree_for_each_key(b, t, k)
 147                         if (!bkey_deleted(k))
 148                                 btree_keys_account_key_add(&nr, t - b->set, k);
 149
 150         BUG_ON(memcmp(&nr, &b->nr, sizeof(nr)));
 151 }
 152
 153 static void bch2_btree_node_iter_next_check(struct btree_node_iter *_iter,
 154                                             struct btree *b)
 155 {
 156         struct btree_node_iter iter = *_iter;
 157         const struct bkey_packed *k, *n;
 158
 159         k = bch2_btree_node_iter_peek_all(&iter, b);
 160         __bch2_btree_node_iter_advance(&iter, b);
 161         n = bch2_btree_node_iter_peek_all(&iter, b);
 162
 163         bkey_unpack_key(b, k);
 164
 165         if (n &&
 166             bkey_iter_cmp(b, k, n) > 0) {
 167                 struct btree_node_iter_set *set;
 168                 struct bkey ku = bkey_unpack_key(b, k);
 169                 struct bkey nu = bkey_unpack_key(b, n);
 170                 char buf1[80], buf2[80];
 171
 172                 bch2_dump_btree_node(NULL, b);
 173                 bch2_bkey_to_text(&PBUF(buf1), &ku);
 174                 bch2_bkey_to_text(&PBUF(buf2), &nu);
 175                 printk(KERN_ERR "out of order/overlapping:\n%s\n%s\n",
 176                        buf1, buf2);
 177                 printk(KERN_ERR "iter was:");
 178
 179                 btree_node_iter_for_each(_iter, set) {
 180                         struct bkey_packed *k = __btree_node_offset_to_key(b, set->k);
 181                         struct bset_tree *t = bch2_bkey_to_bset(b, k);
 182                         printk(" [%zi %zi]", t - b->set,
 183                                k->_data - bset(b, t)->_data);
 184                 }
 185                 panic("\n");
 186         }
 187 }
 188
 189 void bch2_btree_node_iter_verify(struct btree_node_iter *iter,
 190                                  struct btree *b)
 191 {
 192         struct btree_node_iter_set *set, *s2;
 193         struct bkey_packed *k, *p;
 194         struct bset_tree *t;
 195
 196         if (bch2_btree_node_iter_end(iter))
 197                 return;
 198
 199         /* Verify no duplicates: */
 200         btree_node_iter_for_each(iter, set)
 201                 btree_node_iter_for_each(iter, s2)
 202                         BUG_ON(set != s2 && set->end == s2->end);
 203
 204         /* Verify that set->end is correct: */
 205         btree_node_iter_for_each(iter, set) {
 206                 for_each_bset(b, t)
 207                         if (set->end == t->end_offset)
 208                                 goto found;
 209                 BUG();
 210 found:
 211                 BUG_ON(set->k < btree_bkey_first_offset(t) ||
 212                        set->k >= t->end_offset);
 213         }
 214
 215         /* Verify iterator is sorted: */
 216         btree_node_iter_for_each(iter, set)
 217                 BUG_ON(set != iter->data &&
 218                        btree_node_iter_cmp(b, set[-1], set[0]) > 0);
 219
 220         k = bch2_btree_node_iter_peek_all(iter, b);
 221
 222         for_each_bset(b, t) {
 223                 if (iter->data[0].end == t->end_offset)
 224                         continue;
 225
 226                 p = bch2_bkey_prev_all(b, t,
 227                         bch2_btree_node_iter_bset_pos(iter, b, t));
 228
 229                 BUG_ON(p && bkey_iter_cmp(b, k, p) < 0);
 230         }
 231 }
 232
 233 void bch2_verify_insert_pos(struct btree *b, struct bkey_packed *where,
 234                             struct bkey_packed *insert, unsigned clobber_u64s)
 235 {
 236         struct bset_tree *t = bch2_bkey_to_bset(b, where);
 237         struct bkey_packed *prev = bch2_bkey_prev_all(b, t, where);
 238         struct bkey_packed *next = (void *) (where->_data + clobber_u64s);
 239 #if 0
 240         BUG_ON(prev &&
 241                bkey_iter_cmp(b, prev, insert) > 0);
 242 #else
 243         if (prev &&
 244             bkey_iter_cmp(b, prev, insert) > 0) {
 245                 struct bkey k1 = bkey_unpack_key(b, prev);
 246                 struct bkey k2 = bkey_unpack_key(b, insert);
 247                 char buf1[100];
 248                 char buf2[100];
 249
 250                 bch2_dump_btree_node(NULL, b);
 251                 bch2_bkey_to_text(&PBUF(buf1), &k1);
 252                 bch2_bkey_to_text(&PBUF(buf2), &k2);
 253
 254                 panic("prev > insert:\n"
 255                       "prev    key %s\n"
 256                       "insert  key %s\n",
 257                       buf1, buf2);
 258         }
 259 #endif
 260 #if 0
 261         BUG_ON(next != btree_bkey_last(b, t) &&
 262                bkey_iter_cmp(b, insert, next) > 0);
 263 #else
 264         if (next != btree_bkey_last(b, t) &&
 265             bkey_iter_cmp(b, insert, next) > 0) {
 266                 struct bkey k1 = bkey_unpack_key(b, insert);
 267                 struct bkey k2 = bkey_unpack_key(b, next);
 268                 char buf1[100];
 269                 char buf2[100];
 270
 271                 bch2_dump_btree_node(NULL, b);
 272                 bch2_bkey_to_text(&PBUF(buf1), &k1);
 273                 bch2_bkey_to_text(&PBUF(buf2), &k2);
 274
 275                 panic("insert > next:\n"
 276                       "insert  key %s\n"
 277                       "next    key %s\n",
 278                       buf1, buf2);
 279         }
 280 #endif
 281 }
 282
 283 #else
 284
 285 static inline void bch2_btree_node_iter_next_check(struct btree_node_iter *iter,
 286                                                    struct btree *b) {}
 287
 288 #endif
 289
 290 /* Auxiliary search trees */
 291
 292 #define BFLOAT_FAILED_UNPACKED  U8_MAX
 293 #define BFLOAT_FAILED           U8_MAX
 294
 295 struct bkey_float {
 296         u8              exponent;
 297         u8              key_offset;
 298         u16             mantissa;
 299 };
 300 #define BKEY_MANTISSA_BITS      16
 301
 302 static unsigned bkey_float_byte_offset(unsigned idx)
 303 {
 304         return idx * sizeof(struct bkey_float);
 305 }
 306
 307 struct ro_aux_tree {
 308         struct bkey_float       f[0];
 309 };
 310
 311 struct rw_aux_tree {
 312         u16             offset;
 313         struct bpos     k;
 314 };
 315
 316 static unsigned bset_aux_tree_buf_end(const struct bset_tree *t)
 317 {
 318         BUG_ON(t->aux_data_offset == U16_MAX);
 319
 320         switch (bset_aux_tree_type(t)) {
 321         case BSET_NO_AUX_TREE:
 322                 return t->aux_data_offset;
 323         case BSET_RO_AUX_TREE:
 324                 return t->aux_data_offset +
 325                         DIV_ROUND_UP(t->size * sizeof(struct bkey_float) +
 326                                      t->size * sizeof(u8), 8);
 327         case BSET_RW_AUX_TREE:
 328                 return t->aux_data_offset +
 329                         DIV_ROUND_UP(sizeof(struct rw_aux_tree) * t->size, 8);
 330         default:
 331                 BUG();
 332         }
 333 }
 334
 335 static unsigned bset_aux_tree_buf_start(const struct btree *b,
 336                                         const struct bset_tree *t)
 337 {
 338         return t == b->set
 339                 ? DIV_ROUND_UP(b->unpack_fn_len, 8)
 340                 : bset_aux_tree_buf_end(t - 1);
 341 }
 342
 343 static void *__aux_tree_base(const struct btree *b,
 344                              const struct bset_tree *t)
 345 {
 346         return b->aux_data + t->aux_data_offset * 8;
 347 }
 348
 349 static struct ro_aux_tree *ro_aux_tree_base(const struct btree *b,
 350                                             const struct bset_tree *t)
 351 {
 352         EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
 353
 354         return __aux_tree_base(b, t);
 355 }
 356
 357 static u8 *ro_aux_tree_prev(const struct btree *b,
 358                             const struct bset_tree *t)
 359 {
 360         EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
 361
 362         return __aux_tree_base(b, t) + bkey_float_byte_offset(t->size);
 363 }
 364
 365 static struct bkey_float *bkey_float(const struct btree *b,
 366                                      const struct bset_tree *t,
 367                                      unsigned idx)
 368 {
 369         return ro_aux_tree_base(b, t)->f + idx;
 370 }
 371
 372 static void bset_aux_tree_verify(const struct btree *b)
 373 {
 374 #ifdef CONFIG_BCACHEFS_DEBUG
 375         const struct bset_tree *t;
 376
 377         for_each_bset(b, t) {
 378                 if (t->aux_data_offset == U16_MAX)
 379                         continue;
 380
 381                 BUG_ON(t != b->set &&
 382                        t[-1].aux_data_offset == U16_MAX);
 383
 384                 BUG_ON(t->aux_data_offset < bset_aux_tree_buf_start(b, t));
 385                 BUG_ON(t->aux_data_offset > btree_aux_data_u64s(b));
 386                 BUG_ON(bset_aux_tree_buf_end(t) > btree_aux_data_u64s(b));
 387         }
 388 #endif
 389 }
 390
 391 void bch2_btree_keys_init(struct btree *b)
 392 {
 393         unsigned i;
 394
 395         b->nsets                = 0;
 396         memset(&b->nr, 0, sizeof(b->nr));
 397
 398         for (i = 0; i < MAX_BSETS; i++)
 399                 b->set[i].data_offset = U16_MAX;
 400
 401         bch2_bset_set_no_aux_tree(b, b->set);
 402 }
 403
 404 /* Binary tree stuff for auxiliary search trees */
 405
 406 /*
 407  * Cacheline/offset <-> bkey pointer arithmetic:
 408  *
 409  * t->tree is a binary search tree in an array; each node corresponds to a key
 410  * in one cacheline in t->set (BSET_CACHELINE bytes).
 411  *
 412  * This means we don't have to store the full index of the key that a node in
 413  * the binary tree points to; eytzinger1_to_inorder() gives us the cacheline, and
 414  * then bkey_float->m gives us the offset within that cacheline, in units of 8
 415  * bytes.
 416  *
 417  * cacheline_to_bkey() and friends abstract out all the pointer arithmetic to
 418  * make this work.
 419  *
 420  * To construct the bfloat for an arbitrary key we need to know what the key
 421  * immediately preceding it is: we have to check if the two keys differ in the
 422  * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size
 423  * of the previous key so we can walk backwards to it from t->tree[j]'s key.
 424  */
 425
 426 static inline void *bset_cacheline(const struct btree *b,
 427                                    const struct bset_tree *t,
 428                                    unsigned cacheline)
 429 {
 430         return (void *) round_down((unsigned long) btree_bkey_first(b, t),
 431                                    L1_CACHE_BYTES) +
 432                 cacheline * BSET_CACHELINE;
 433 }
 434
 435 static struct bkey_packed *cacheline_to_bkey(const struct btree *b,
 436                                              const struct bset_tree *t,
 437                                              unsigned cacheline,
 438                                              unsigned offset)
 439 {
 440         return bset_cacheline(b, t, cacheline) + offset * 8;
 441 }
 442
 443 static unsigned bkey_to_cacheline(const struct btree *b,
 444                                   const struct bset_tree *t,
 445                                   const struct bkey_packed *k)
 446 {
 447         return ((void *) k - bset_cacheline(b, t, 0)) / BSET_CACHELINE;
 448 }
 449
 450 static ssize_t __bkey_to_cacheline_offset(const struct btree *b,
 451                                           const struct bset_tree *t,
 452                                           unsigned cacheline,
 453                                           const struct bkey_packed *k)
 454 {
 455         return (u64 *) k - (u64 *) bset_cacheline(b, t, cacheline);
 456 }
 457
 458 static unsigned bkey_to_cacheline_offset(const struct btree *b,
 459                                          const struct bset_tree *t,
 460                                          unsigned cacheline,
 461                                          const struct bkey_packed *k)
 462 {
 463         size_t m = __bkey_to_cacheline_offset(b, t, cacheline, k);
 464
 465         EBUG_ON(m > U8_MAX);
 466         return m;
 467 }
 468
 469 static inline struct bkey_packed *tree_to_bkey(const struct btree *b,
 470                                                const struct bset_tree *t,
 471                                                unsigned j)
 472 {
 473         return cacheline_to_bkey(b, t,
 474                         __eytzinger1_to_inorder(j, t->size, t->extra),
 475                         bkey_float(b, t, j)->key_offset);
 476 }
 477
 478 static struct bkey_packed *tree_to_prev_bkey(const struct btree *b,
 479                                              const struct bset_tree *t,
 480                                              unsigned j)
 481 {
 482         unsigned prev_u64s = ro_aux_tree_prev(b, t)[j];
 483
 484         return (void *) (tree_to_bkey(b, t, j)->_data - prev_u64s);
 485 }
 486
 487 static struct rw_aux_tree *rw_aux_tree(const struct btree *b,
 488                                        const struct bset_tree *t)
 489 {
 490         EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE);
 491
 492         return __aux_tree_base(b, t);
 493 }
 494
 495 /*
 496  * For the write set - the one we're currently inserting keys into - we don't
 497  * maintain a full search tree, we just keep a simple lookup table in t->prev.
 498  */
 499 static struct bkey_packed *rw_aux_to_bkey(const struct btree *b,
 500                                           struct bset_tree *t,
 501                                           unsigned j)
 502 {
 503         return __btree_node_offset_to_key(b, rw_aux_tree(b, t)[j].offset);
 504 }
 505
 506 static void rw_aux_tree_set(const struct btree *b, struct bset_tree *t,
 507                             unsigned j, struct bkey_packed *k)
 508 {
 509         EBUG_ON(k >= btree_bkey_last(b, t));
 510
 511         rw_aux_tree(b, t)[j] = (struct rw_aux_tree) {
 512                 .offset = __btree_node_key_to_offset(b, k),
 513                 .k      = bkey_unpack_pos(b, k),
 514         };
 515 }
 516
 517 static void bch2_bset_verify_rw_aux_tree(struct btree *b,
 518                                         struct bset_tree *t)
 519 {
 520         struct bkey_packed *k = btree_bkey_first(b, t);
 521         unsigned j = 0;
 522
 523         if (!bch2_expensive_debug_checks)
 524                 return;
 525
 526         BUG_ON(bset_has_ro_aux_tree(t));
 527
 528         if (!bset_has_rw_aux_tree(t))
 529                 return;
 530
 531         BUG_ON(t->size < 1);
 532         BUG_ON(rw_aux_to_bkey(b, t, j) != k);
 533
 534         goto start;
 535         while (1) {
 536                 if (rw_aux_to_bkey(b, t, j) == k) {
 537                         BUG_ON(bpos_cmp(rw_aux_tree(b, t)[j].k,
 538                                         bkey_unpack_pos(b, k)));
 539 start:
 540                         if (++j == t->size)
 541                                 break;
 542
 543                         BUG_ON(rw_aux_tree(b, t)[j].offset <=
 544                                rw_aux_tree(b, t)[j - 1].offset);
 545                 }
 546
 547                 k = bkey_next(k);
 548                 BUG_ON(k >= btree_bkey_last(b, t));
 549         }
 550 }
 551
 552 /* returns idx of first entry >= offset: */
 553 static unsigned rw_aux_tree_bsearch(struct btree *b,
 554                                     struct bset_tree *t,
 555                                     unsigned offset)
 556 {
 557         unsigned bset_offs = offset - btree_bkey_first_offset(t);
 558         unsigned bset_u64s = t->end_offset - btree_bkey_first_offset(t);
 559         unsigned idx = bset_u64s ? bset_offs * t->size / bset_u64s : 0;
 560
 561         EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE);
 562         EBUG_ON(!t->size);
 563         EBUG_ON(idx > t->size);
 564
 565         while (idx < t->size &&
 566                rw_aux_tree(b, t)[idx].offset < offset)
 567                 idx++;
 568
 569         while (idx &&
 570                rw_aux_tree(b, t)[idx - 1].offset >= offset)
 571                 idx--;
 572
 573         EBUG_ON(idx < t->size &&
 574                 rw_aux_tree(b, t)[idx].offset < offset);
 575         EBUG_ON(idx && rw_aux_tree(b, t)[idx - 1].offset >= offset);
 576         EBUG_ON(idx + 1 < t->size &&
 577                 rw_aux_tree(b, t)[idx].offset ==
 578                 rw_aux_tree(b, t)[idx + 1].offset);
 579
 580         return idx;
 581 }
 582
 583 static inline unsigned bkey_mantissa(const struct bkey_packed *k,
 584                                      const struct bkey_float *f,
 585                                      unsigned idx)
 586 {
 587         u64 v;
 588
 589         EBUG_ON(!bkey_packed(k));
 590
 591         v = get_unaligned((u64 *) (((u8 *) k->_data) + (f->exponent >> 3)));
 592
 593         /*
 594          * In little endian, we're shifting off low bits (and then the bits we
 595          * want are at the low end), in big endian we're shifting off high bits
 596          * (and then the bits we want are at the high end, so we shift them
 597          * back down):
 598          */
 599 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 600         v >>= f->exponent & 7;
 601 #else
 602         v >>= 64 - (f->exponent & 7) - BKEY_MANTISSA_BITS;
 603 #endif
 604         return (u16) v;
 605 }
 606
 607 __always_inline
 608 static inline void __make_bfloat(struct btree *b, struct bset_tree *t,
 609                                  unsigned j,
 610                                  struct bkey_packed *min_key,
 611                                  struct bkey_packed *max_key)
 612 {
 613         struct bkey_float *f = bkey_float(b, t, j);
 614         struct bkey_packed *m = tree_to_bkey(b, t, j);
 615         struct bkey_packed *l = is_power_of_2(j)
 616                 ? min_key
 617                 : tree_to_prev_bkey(b, t, j >> ffs(j));
 618         struct bkey_packed *r = is_power_of_2(j + 1)
 619                 ? max_key
 620                 : tree_to_bkey(b, t, j >> (ffz(j) + 1));
 621         unsigned mantissa;
 622         int shift, exponent, high_bit;
 623
 624         /*
 625          * for failed bfloats, the lookup code falls back to comparing against
 626          * the original key.
 627          */
 628
 629         if (!bkey_packed(l) || !bkey_packed(r) || !bkey_packed(m) ||
 630             !b->nr_key_bits) {
 631                 f->exponent = BFLOAT_FAILED_UNPACKED;
 632                 return;
 633         }
 634
 635         /*
 636          * The greatest differing bit of l and r is the first bit we must
 637          * include in the bfloat mantissa we're creating in order to do
 638          * comparisons - that bit always becomes the high bit of
 639          * bfloat->mantissa, and thus the exponent we're calculating here is
 640          * the position of what will become the low bit in bfloat->mantissa:
 641          *
 642          * Note that this may be negative - we may be running off the low end
 643          * of the key: we handle this later:
 644          */
 645         high_bit = max(bch2_bkey_greatest_differing_bit(b, l, r),
 646                        min_t(unsigned, BKEY_MANTISSA_BITS, b->nr_key_bits) - 1);
 647         exponent = high_bit - (BKEY_MANTISSA_BITS - 1);
 648
 649         /*
 650          * Then we calculate the actual shift value, from the start of the key
 651          * (k->_data), to get the key bits starting at exponent:
 652          */
 653 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 654         shift = (int) (b->format.key_u64s * 64 - b->nr_key_bits) + exponent;
 655
 656         EBUG_ON(shift + BKEY_MANTISSA_BITS > b->format.key_u64s * 64);
 657 #else
 658         shift = high_bit_offset +
 659                 b->nr_key_bits -
 660                 exponent -
 661                 BKEY_MANTISSA_BITS;
 662
 663         EBUG_ON(shift < KEY_PACKED_BITS_START);
 664 #endif
 665         EBUG_ON(shift < 0 || shift >= BFLOAT_FAILED);
 666
 667         f->exponent = shift;
 668         mantissa = bkey_mantissa(m, f, j);
 669
 670         /*
 671          * If we've got garbage bits, set them to all 1s - it's legal for the
 672          * bfloat to compare larger than the original key, but not smaller:
 673          */
 674         if (exponent < 0)
 675                 mantissa |= ~(~0U << -exponent);
 676
 677         f->mantissa = mantissa;
 678 }
 679
 680 static void make_bfloat(struct btree *b, struct bset_tree *t,
 681                         unsigned j,
 682                         struct bkey_packed *min_key,
 683                         struct bkey_packed *max_key)
 684 {
 685         struct bkey_i *k;
 686
 687         if (is_power_of_2(j) &&
 688             !min_key->u64s) {
 689                 if (!bkey_pack_pos(min_key, b->data->min_key, b)) {
 690                         k = (void *) min_key;
 691                         bkey_init(&k->k);
 692                         k->k.p = b->data->min_key;
 693                 }
 694         }
 695
 696         if (is_power_of_2(j + 1) &&
 697             !max_key->u64s) {
 698                 if (!bkey_pack_pos(max_key, b->data->max_key, b)) {
 699                         k = (void *) max_key;
 700                         bkey_init(&k->k);
 701                         k->k.p = b->data->max_key;
 702                 }
 703         }
 704
 705         __make_bfloat(b, t, j, min_key, max_key);
 706 }
 707
 708 /* bytes remaining - only valid for last bset: */
 709 static unsigned __bset_tree_capacity(const struct btree *b, const struct bset_tree *t)
 710 {
 711         bset_aux_tree_verify(b);
 712
 713         return btree_aux_data_bytes(b) - t->aux_data_offset * sizeof(u64);
 714 }
 715
 716 static unsigned bset_ro_tree_capacity(const struct btree *b, const struct bset_tree *t)
 717 {
 718         return __bset_tree_capacity(b, t) /
 719                 (sizeof(struct bkey_float) + sizeof(u8));
 720 }
 721
 722 static unsigned bset_rw_tree_capacity(const struct btree *b, const struct bset_tree *t)
 723 {
 724         return __bset_tree_capacity(b, t) / sizeof(struct rw_aux_tree);
 725 }
 726
 727 static noinline void __build_rw_aux_tree(struct btree *b, struct bset_tree *t)
 728 {
 729         struct bkey_packed *k;
 730
 731         t->size = 1;
 732         t->extra = BSET_RW_AUX_TREE_VAL;
 733         rw_aux_tree(b, t)[0].offset =
 734                 __btree_node_key_to_offset(b, btree_bkey_first(b, t));
 735
 736         bset_tree_for_each_key(b, t, k) {
 737                 if (t->size == bset_rw_tree_capacity(b, t))
 738                         break;
 739
 740                 if ((void *) k - (void *) rw_aux_to_bkey(b, t, t->size - 1) >
 741                     L1_CACHE_BYTES)
 742                         rw_aux_tree_set(b, t, t->size++, k);
 743         }
 744 }
 745
 746 static noinline void __build_ro_aux_tree(struct btree *b, struct bset_tree *t)
 747 {
 748         struct bkey_packed *prev = NULL, *k = btree_bkey_first(b, t);
 749         struct bkey_i min_key, max_key;
 750         unsigned j, cacheline = 1;
 751
 752         t->size = min(bkey_to_cacheline(b, t, btree_bkey_last(b, t)),
 753                       bset_ro_tree_capacity(b, t));
 754 retry:
 755         if (t->size < 2) {
 756                 t->size = 0;
 757                 t->extra = BSET_NO_AUX_TREE_VAL;
 758                 return;
 759         }
 760
 761         t->extra = (t->size - rounddown_pow_of_two(t->size - 1)) << 1;
 762
 763         /* First we figure out where the first key in each cacheline is */
 764         eytzinger1_for_each(j, t->size) {
 765                 while (bkey_to_cacheline(b, t, k) < cacheline)
 766                         prev = k, k = bkey_next(k);
 767
 768                 if (k >= btree_bkey_last(b, t)) {
 769                         /* XXX: this path sucks */
 770                         t->size--;
 771                         goto retry;
 772                 }
 773
 774                 ro_aux_tree_prev(b, t)[j] = prev->u64s;
 775                 bkey_float(b, t, j)->key_offset =
 776                         bkey_to_cacheline_offset(b, t, cacheline++, k);
 777
 778                 EBUG_ON(tree_to_prev_bkey(b, t, j) != prev);
 779                 EBUG_ON(tree_to_bkey(b, t, j) != k);
 780         }
 781
 782         while (k != btree_bkey_last(b, t))
 783                 prev = k, k = bkey_next(k);
 784
 785         if (!bkey_pack_pos(bkey_to_packed(&min_key), b->data->min_key, b)) {
 786                 bkey_init(&min_key.k);
 787                 min_key.k.p = b->data->min_key;
 788         }
 789
 790         if (!bkey_pack_pos(bkey_to_packed(&max_key), b->data->max_key, b)) {
 791                 bkey_init(&max_key.k);
 792                 max_key.k.p = b->data->max_key;
 793         }
 794
 795         /* Then we build the tree */
 796         eytzinger1_for_each(j, t->size)
 797                 __make_bfloat(b, t, j,
 798                               bkey_to_packed(&min_key),
 799                               bkey_to_packed(&max_key));
 800 }
 801
 802 static void bset_alloc_tree(struct btree *b, struct bset_tree *t)
 803 {
 804         struct bset_tree *i;
 805
 806         for (i = b->set; i != t; i++)
 807                 BUG_ON(bset_has_rw_aux_tree(i));
 808
 809         bch2_bset_set_no_aux_tree(b, t);
 810
 811         /* round up to next cacheline: */
 812         t->aux_data_offset = round_up(bset_aux_tree_buf_start(b, t),
 813                                       SMP_CACHE_BYTES / sizeof(u64));
 814
 815         bset_aux_tree_verify(b);
 816 }
 817
 818 void bch2_bset_build_aux_tree(struct btree *b, struct bset_tree *t,
 819                              bool writeable)
 820 {
 821         if (writeable
 822             ? bset_has_rw_aux_tree(t)
 823             : bset_has_ro_aux_tree(t))
 824                 return;
 825
 826         bset_alloc_tree(b, t);
 827
 828         if (!__bset_tree_capacity(b, t))
 829                 return;
 830
 831         if (writeable)
 832                 __build_rw_aux_tree(b, t);
 833         else
 834                 __build_ro_aux_tree(b, t);
 835
 836         bset_aux_tree_verify(b);
 837 }
 838
 839 void bch2_bset_init_first(struct btree *b, struct bset *i)
 840 {
 841         struct bset_tree *t;
 842
 843         BUG_ON(b->nsets);
 844
 845         memset(i, 0, sizeof(*i));
 846         get_random_bytes(&i->seq, sizeof(i->seq));
 847         SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN);
 848
 849         t = &b->set[b->nsets++];
 850         set_btree_bset(b, t, i);
 851 }
 852
 853 void bch2_bset_init_next(struct bch_fs *c, struct btree *b,
 854                          struct btree_node_entry *bne)
 855 {
 856         struct bset *i = &bne->keys;
 857         struct bset_tree *t;
 858
 859         BUG_ON(bset_byte_offset(b, bne) >= btree_bytes(c));
 860         BUG_ON((void *) bne < (void *) btree_bkey_last(b, bset_tree_last(b)));
 861         BUG_ON(b->nsets >= MAX_BSETS);
 862
 863         memset(i, 0, sizeof(*i));
 864         i->seq = btree_bset_first(b)->seq;
 865         SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN);
 866
 867         t = &b->set[b->nsets++];
 868         set_btree_bset(b, t, i);
 869 }
 870
 871 /*
 872  * find _some_ key in the same bset as @k that precedes @k - not necessarily the
 873  * immediate predecessor:
 874  */
 875 static struct bkey_packed *__bkey_prev(struct btree *b, struct bset_tree *t,
 876                                        struct bkey_packed *k)
 877 {
 878         struct bkey_packed *p;
 879         unsigned offset;
 880         int j;
 881
 882         EBUG_ON(k < btree_bkey_first(b, t) ||
 883                 k > btree_bkey_last(b, t));
 884
 885         if (k == btree_bkey_first(b, t))
 886                 return NULL;
 887
 888         switch (bset_aux_tree_type(t)) {
 889         case BSET_NO_AUX_TREE:
 890                 p = btree_bkey_first(b, t);
 891                 break;
 892         case BSET_RO_AUX_TREE:
 893                 j = min_t(unsigned, t->size - 1, bkey_to_cacheline(b, t, k));
 894
 895                 do {
 896                         p = j ? tree_to_bkey(b, t,
 897                                         __inorder_to_eytzinger1(j--,
 898                                                         t->size, t->extra))
 899                               : btree_bkey_first(b, t);
 900                 } while (p >= k);
 901                 break;
 902         case BSET_RW_AUX_TREE:
 903                 offset = __btree_node_key_to_offset(b, k);
 904                 j = rw_aux_tree_bsearch(b, t, offset);
 905                 p = j ? rw_aux_to_bkey(b, t, j - 1)
 906                       : btree_bkey_first(b, t);
 907                 break;
 908         }
 909
 910         return p;
 911 }
 912
 913 struct bkey_packed *bch2_bkey_prev_filter(struct btree *b,
 914                                           struct bset_tree *t,
 915                                           struct bkey_packed *k,
 916                                           unsigned min_key_type)
 917 {
 918         struct bkey_packed *p, *i, *ret = NULL, *orig_k = k;
 919
 920         while ((p = __bkey_prev(b, t, k)) && !ret) {
 921                 for (i = p; i != k; i = bkey_next(i))
 922                         if (i->type >= min_key_type)
 923                                 ret = i;
 924
 925                 k = p;
 926         }
 927
 928         if (bch2_expensive_debug_checks) {
 929                 BUG_ON(ret >= orig_k);
 930
 931                 for (i = ret
 932                         ? bkey_next(ret)
 933                         : btree_bkey_first(b, t);
 934                      i != orig_k;
 935                      i = bkey_next(i))
 936                         BUG_ON(i->type >= min_key_type);
 937         }
 938
 939         return ret;
 940 }
 941
 942 /* Insert */
 943
 944 static void rw_aux_tree_fix_invalidated_key(struct btree *b,
 945                                             struct bset_tree *t,
 946                                             struct bkey_packed *k)
 947 {
 948         unsigned offset = __btree_node_key_to_offset(b, k);
 949         unsigned j = rw_aux_tree_bsearch(b, t, offset);
 950
 951         if (j < t->size &&
 952             rw_aux_tree(b, t)[j].offset == offset)
 953                 rw_aux_tree_set(b, t, j, k);
 954
 955         bch2_bset_verify_rw_aux_tree(b, t);
 956 }
 957
 958 static void ro_aux_tree_fix_invalidated_key(struct btree *b,
 959                                             struct bset_tree *t,
 960                                             struct bkey_packed *k)
 961 {
 962         struct bkey_packed min_key, max_key;
 963         unsigned inorder, j;
 964
 965         EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
 966
 967         /* signal to make_bfloat() that they're uninitialized: */
 968         min_key.u64s = max_key.u64s = 0;
 969
 970         if (bkey_next(k) == btree_bkey_last(b, t)) {
 971                 for (j = 1; j < t->size; j = j * 2 + 1)
 972                         make_bfloat(b, t, j, &min_key, &max_key);
 973         }
 974
 975         inorder = bkey_to_cacheline(b, t, k);
 976
 977         if (inorder &&
 978             inorder < t->size) {
 979                 j = __inorder_to_eytzinger1(inorder, t->size, t->extra);
 980
 981                 if (k == tree_to_bkey(b, t, j)) {
 982                         /* Fix the node this key corresponds to */
 983                         make_bfloat(b, t, j, &min_key, &max_key);
 984
 985                         /* Children for which this key is the right boundary */
 986                         for (j = eytzinger1_left_child(j);
 987                              j < t->size;
 988                              j = eytzinger1_right_child(j))
 989                                 make_bfloat(b, t, j, &min_key, &max_key);
 990                 }
 991         }
 992
 993         if (inorder + 1 < t->size) {
 994                 j = __inorder_to_eytzinger1(inorder + 1, t->size, t->extra);
 995
 996                 if (k == tree_to_prev_bkey(b, t, j)) {
 997                         make_bfloat(b, t, j, &min_key, &max_key);
 998
 999                         /* Children for which this key is the left boundary */
1000                         for (j = eytzinger1_right_child(j);
1001                              j < t->size;
1002                              j = eytzinger1_left_child(j))
1003                                 make_bfloat(b, t, j, &min_key, &max_key);
1004                 }
1005         }
1006 }
1007
1008 /**
1009  * bch2_bset_fix_invalidated_key() - given an existing  key @k that has been
1010  * modified, fix any auxiliary search tree by remaking all the nodes in the
1011  * auxiliary search tree that @k corresponds to
1012  */
1013 void bch2_bset_fix_invalidated_key(struct btree *b, struct bkey_packed *k)
1014 {
1015         struct bset_tree *t = bch2_bkey_to_bset(b, k);
1016
1017         switch (bset_aux_tree_type(t)) {
1018         case BSET_NO_AUX_TREE:
1019                 break;
1020         case BSET_RO_AUX_TREE:
1021                 ro_aux_tree_fix_invalidated_key(b, t, k);
1022                 break;
1023         case BSET_RW_AUX_TREE:
1024                 rw_aux_tree_fix_invalidated_key(b, t, k);
1025                 break;
1026         }
1027 }
1028
1029 static void bch2_bset_fix_lookup_table(struct btree *b,
1030                                        struct bset_tree *t,
1031                                        struct bkey_packed *_where,
1032                                        unsigned clobber_u64s,
1033                                        unsigned new_u64s)
1034 {
1035         int shift = new_u64s - clobber_u64s;
1036         unsigned l, j, where = __btree_node_key_to_offset(b, _where);
1037
1038         EBUG_ON(bset_has_ro_aux_tree(t));
1039
1040         if (!bset_has_rw_aux_tree(t))
1041                 return;
1042
1043         /* returns first entry >= where */
1044         l = rw_aux_tree_bsearch(b, t, where);
1045
1046         if (!l) /* never delete first entry */
1047                 l++;
1048         else if (l < t->size &&
1049                  where < t->end_offset &&
1050                  rw_aux_tree(b, t)[l].offset == where)
1051                 rw_aux_tree_set(b, t, l++, _where);
1052
1053         /* l now > where */
1054
1055         for (j = l;
1056              j < t->size &&
1057              rw_aux_tree(b, t)[j].offset < where + clobber_u64s;
1058              j++)
1059                 ;
1060
1061         if (j < t->size &&
1062             rw_aux_tree(b, t)[j].offset + shift ==
1063             rw_aux_tree(b, t)[l - 1].offset)
1064                 j++;
1065
1066         memmove(&rw_aux_tree(b, t)[l],
1067                 &rw_aux_tree(b, t)[j],
1068                 (void *) &rw_aux_tree(b, t)[t->size] -
1069                 (void *) &rw_aux_tree(b, t)[j]);
1070         t->size -= j - l;
1071
1072         for (j = l; j < t->size; j++)
1073                rw_aux_tree(b, t)[j].offset += shift;
1074
1075         EBUG_ON(l < t->size &&
1076                 rw_aux_tree(b, t)[l].offset ==
1077                 rw_aux_tree(b, t)[l - 1].offset);
1078
1079         if (t->size < bset_rw_tree_capacity(b, t) &&
1080             (l < t->size
1081              ? rw_aux_tree(b, t)[l].offset
1082              : t->end_offset) -
1083             rw_aux_tree(b, t)[l - 1].offset >
1084             L1_CACHE_BYTES / sizeof(u64)) {
1085                 struct bkey_packed *start = rw_aux_to_bkey(b, t, l - 1);
1086                 struct bkey_packed *end = l < t->size
1087                         ? rw_aux_to_bkey(b, t, l)
1088                         : btree_bkey_last(b, t);
1089                 struct bkey_packed *k = start;
1090
1091                 while (1) {
1092                         k = bkey_next(k);
1093                         if (k == end)
1094                                 break;
1095
1096                         if ((void *) k - (void *) start >= L1_CACHE_BYTES) {
1097                                 memmove(&rw_aux_tree(b, t)[l + 1],
1098                                         &rw_aux_tree(b, t)[l],
1099                                         (void *) &rw_aux_tree(b, t)[t->size] -
1100                                         (void *) &rw_aux_tree(b, t)[l]);
1101                                 t->size++;
1102                                 rw_aux_tree_set(b, t, l, k);
1103                                 break;
1104                         }
1105                 }
1106         }
1107
1108         bch2_bset_verify_rw_aux_tree(b, t);
1109         bset_aux_tree_verify(b);
1110 }
1111
1112 void bch2_bset_insert(struct btree *b,
1113                       struct btree_node_iter *iter,
1114                       struct bkey_packed *where,
1115                       struct bkey_i *insert,
1116                       unsigned clobber_u64s)
1117 {
1118         struct bkey_format *f = &b->format;
1119         struct bset_tree *t = bset_tree_last(b);
1120         struct bkey_packed packed, *src = bkey_to_packed(insert);
1121
1122         bch2_bset_verify_rw_aux_tree(b, t);
1123         bch2_verify_insert_pos(b, where, bkey_to_packed(insert), clobber_u64s);
1124
1125         if (bch2_bkey_pack_key(&packed, &insert->k, f))
1126                 src = &packed;
1127
1128         if (!bkey_deleted(&insert->k))
1129                 btree_keys_account_key_add(&b->nr, t - b->set, src);
1130
1131         if (src->u64s != clobber_u64s) {
1132                 u64 *src_p = where->_data + clobber_u64s;
1133                 u64 *dst_p = where->_data + src->u64s;
1134
1135                 EBUG_ON((int) le16_to_cpu(bset(b, t)->u64s) <
1136                         (int) clobber_u64s - src->u64s);
1137
1138                 memmove_u64s(dst_p, src_p, btree_bkey_last(b, t)->_data - src_p);
1139                 le16_add_cpu(&bset(b, t)->u64s, src->u64s - clobber_u64s);
1140                 set_btree_bset_end(b, t);
1141         }
1142
1143         memcpy_u64s(where, src,
1144                     bkeyp_key_u64s(f, src));
1145         memcpy_u64s(bkeyp_val(f, where), &insert->v,
1146                     bkeyp_val_u64s(f, src));
1147
1148         if (src->u64s != clobber_u64s)
1149                 bch2_bset_fix_lookup_table(b, t, where, clobber_u64s, src->u64s);
1150
1151         bch2_verify_btree_nr_keys(b);
1152 }
1153
1154 void bch2_bset_delete(struct btree *b,
1155                       struct bkey_packed *where,
1156                       unsigned clobber_u64s)
1157 {
1158         struct bset_tree *t = bset_tree_last(b);
1159         u64 *src_p = where->_data + clobber_u64s;
1160         u64 *dst_p = where->_data;
1161
1162         bch2_bset_verify_rw_aux_tree(b, t);
1163
1164         EBUG_ON(le16_to_cpu(bset(b, t)->u64s) < clobber_u64s);
1165
1166         memmove_u64s_down(dst_p, src_p, btree_bkey_last(b, t)->_data - src_p);
1167         le16_add_cpu(&bset(b, t)->u64s, -clobber_u64s);
1168         set_btree_bset_end(b, t);
1169
1170         bch2_bset_fix_lookup_table(b, t, where, clobber_u64s, 0);
1171 }
1172
1173 /* Lookup */
1174
1175 __flatten
1176 static struct bkey_packed *bset_search_write_set(const struct btree *b,
1177                                 struct bset_tree *t,
1178                                 struct bpos *search)
1179 {
1180         unsigned l = 0, r = t->size;
1181
1182         while (l + 1 != r) {
1183                 unsigned m = (l + r) >> 1;
1184
1185                 if (bpos_cmp(rw_aux_tree(b, t)[m].k, *search) < 0)
1186                         l = m;
1187                 else
1188                         r = m;
1189         }
1190
1191         return rw_aux_to_bkey(b, t, l);
1192 }
1193
1194 static inline void prefetch_four_cachelines(void *p)
1195 {
1196 #ifdef CONFIG_X86_64
1197         asm(".intel_syntax noprefix;"
1198             "prefetcht0 [%0 - 127 + 64 * 0];"
1199             "prefetcht0 [%0 - 127 + 64 * 1];"
1200             "prefetcht0 [%0 - 127 + 64 * 2];"
1201             "prefetcht0 [%0 - 127 + 64 * 3];"
1202             ".att_syntax prefix;"
1203             :
1204             : "r" (p + 127));
1205 #else
1206         prefetch(p + L1_CACHE_BYTES * 0);
1207         prefetch(p + L1_CACHE_BYTES * 1);
1208         prefetch(p + L1_CACHE_BYTES * 2);
1209         prefetch(p + L1_CACHE_BYTES * 3);
1210 #endif
1211 }
1212
1213 static inline bool bkey_mantissa_bits_dropped(const struct btree *b,
1214                                               const struct bkey_float *f,
1215                                               unsigned idx)
1216 {
1217 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
1218         unsigned key_bits_start = b->format.key_u64s * 64 - b->nr_key_bits;
1219
1220         return f->exponent > key_bits_start;
1221 #else
1222         unsigned key_bits_end = high_bit_offset + b->nr_key_bits;
1223
1224         return f->exponent + BKEY_MANTISSA_BITS < key_bits_end;
1225 #endif
1226 }
1227
1228 __flatten
1229 static struct bkey_packed *bset_search_tree(const struct btree *b,
1230                                 const struct bset_tree *t,
1231                                 const struct bpos *search,
1232                                 const struct bkey_packed *packed_search)
1233 {
1234         struct ro_aux_tree *base = ro_aux_tree_base(b, t);
1235         struct bkey_float *f;
1236         struct bkey_packed *k;
1237         unsigned inorder, n = 1, l, r;
1238         int cmp;
1239
1240         do {
1241                 if (likely(n << 4 < t->size))
1242                         prefetch(&base->f[n << 4]);
1243
1244                 f = &base->f[n];
1245                 if (unlikely(f->exponent >= BFLOAT_FAILED))
1246                         goto slowpath;
1247
1248                 l = f->mantissa;
1249                 r = bkey_mantissa(packed_search, f, n);
1250
1251                 if (unlikely(l == r) && bkey_mantissa_bits_dropped(b, f, n))
1252                         goto slowpath;
1253
1254                 n = n * 2 + (l < r);
1255                 continue;
1256 slowpath:
1257                 k = tree_to_bkey(b, t, n);
1258                 cmp = bkey_cmp_p_or_unp(b, k, packed_search, search);
1259                 if (!cmp)
1260                         return k;
1261
1262                 n = n * 2 + (cmp < 0);
1263         } while (n < t->size);
1264
1265         inorder = __eytzinger1_to_inorder(n >> 1, t->size, t->extra);
1266
1267         /*
1268          * n would have been the node we recursed to - the low bit tells us if
1269          * we recursed left or recursed right.
1270          */
1271         if (likely(!(n & 1))) {
1272                 --inorder;
1273                 if (unlikely(!inorder))
1274                         return btree_bkey_first(b, t);
1275
1276                 f = &base->f[eytzinger1_prev(n >> 1, t->size)];
1277         }
1278
1279         return cacheline_to_bkey(b, t, inorder, f->key_offset);
1280 }
1281
1282 static __always_inline __flatten
1283 struct bkey_packed *__bch2_bset_search(struct btree *b,
1284                                 struct bset_tree *t,
1285                                 struct bpos *search,
1286                                 const struct bkey_packed *lossy_packed_search)
1287 {
1288
1289         /*
1290          * First, we search for a cacheline, then lastly we do a linear search
1291          * within that cacheline.
1292          *
1293          * To search for the cacheline, there's three different possibilities:
1294          *  * The set is too small to have a search tree, so we just do a linear
1295          *    search over the whole set.
1296          *  * The set is the one we're currently inserting into; keeping a full
1297          *    auxiliary search tree up to date would be too expensive, so we
1298          *    use a much simpler lookup table to do a binary search -
1299          *    bset_search_write_set().
1300          *  * Or we use the auxiliary search tree we constructed earlier -
1301          *    bset_search_tree()
1302          */
1303
1304         switch (bset_aux_tree_type(t)) {
1305         case BSET_NO_AUX_TREE:
1306                 return btree_bkey_first(b, t);
1307         case BSET_RW_AUX_TREE:
1308                 return bset_search_write_set(b, t, search);
1309         case BSET_RO_AUX_TREE:
1310                 return bset_search_tree(b, t, search, lossy_packed_search);
1311         default:
1312                 unreachable();
1313         }
1314 }
1315
1316 static __always_inline __flatten
1317 struct bkey_packed *bch2_bset_search_linear(struct btree *b,
1318                                 struct bset_tree *t,
1319                                 struct bpos *search,
1320                                 struct bkey_packed *packed_search,
1321                                 const struct bkey_packed *lossy_packed_search,
1322                                 struct bkey_packed *m)
1323 {
1324         if (lossy_packed_search)
1325                 while (m != btree_bkey_last(b, t) &&
1326                        bkey_iter_cmp_p_or_unp(b, m,
1327                                         lossy_packed_search, search) < 0)
1328                         m = bkey_next(m);
1329
1330         if (!packed_search)
1331                 while (m != btree_bkey_last(b, t) &&
1332                        bkey_iter_pos_cmp(b, m, search) < 0)
1333                         m = bkey_next(m);
1334
1335         if (bch2_expensive_debug_checks) {
1336                 struct bkey_packed *prev = bch2_bkey_prev_all(b, t, m);
1337
1338                 BUG_ON(prev &&
1339                        bkey_iter_cmp_p_or_unp(b, prev,
1340                                         packed_search, search) >= 0);
1341         }
1342
1343         return m;
1344 }
1345
1346 /* Btree node iterator */
1347
1348 static inline void __bch2_btree_node_iter_push(struct btree_node_iter *iter,
1349                               struct btree *b,
1350                               const struct bkey_packed *k,
1351                               const struct bkey_packed *end)
1352 {
1353         if (k != end) {
1354                 struct btree_node_iter_set *pos;
1355
1356                 btree_node_iter_for_each(iter, pos)
1357                         ;
1358
1359                 BUG_ON(pos >= iter->data + ARRAY_SIZE(iter->data));
1360                 *pos = (struct btree_node_iter_set) {
1361                         __btree_node_key_to_offset(b, k),
1362                         __btree_node_key_to_offset(b, end)
1363                 };
1364         }
1365 }
1366
1367 void bch2_btree_node_iter_push(struct btree_node_iter *iter,
1368                                struct btree *b,
1369                                const struct bkey_packed *k,
1370                                const struct bkey_packed *end)
1371 {
1372         __bch2_btree_node_iter_push(iter, b, k, end);
1373         bch2_btree_node_iter_sort(iter, b);
1374 }
1375
1376 noinline __flatten __attribute__((cold))
1377 static void btree_node_iter_init_pack_failed(struct btree_node_iter *iter,
1378                               struct btree *b, struct bpos *search)
1379 {
1380         struct bkey_packed *k;
1381
1382         trace_bkey_pack_pos_fail(search);
1383
1384         bch2_btree_node_iter_init_from_start(iter, b);
1385
1386         while ((k = bch2_btree_node_iter_peek(iter, b)) &&
1387                bkey_iter_pos_cmp(b, k, search) < 0)
1388                 bch2_btree_node_iter_advance(iter, b);
1389 }
1390
1391 /**
1392  * bch_btree_node_iter_init - initialize a btree node iterator, starting from a
1393  * given position
1394  *
1395  * Main entry point to the lookup code for individual btree nodes:
1396  *
1397  * NOTE:
1398  *
1399  * When you don't filter out deleted keys, btree nodes _do_ contain duplicate
1400  * keys. This doesn't matter for most code, but it does matter for lookups.
1401  *
1402  * Some adjacent keys with a string of equal keys:
1403  *      i j k k k k l m
1404  *
1405  * If you search for k, the lookup code isn't guaranteed to return you any
1406  * specific k. The lookup code is conceptually doing a binary search and
1407  * iterating backwards is very expensive so if the pivot happens to land at the
1408  * last k that's what you'll get.
1409  *
1410  * This works out ok, but it's something to be aware of:
1411  *
1412  *  - For non extents, we guarantee that the live key comes last - see
1413  *    btree_node_iter_cmp(), keys_out_of_order(). So the duplicates you don't
1414  *    see will only be deleted keys you don't care about.
1415  *
1416  *  - For extents, deleted keys sort last (see the comment at the top of this
1417  *    file). But when you're searching for extents, you actually want the first
1418  *    key strictly greater than your search key - an extent that compares equal
1419  *    to the search key is going to have 0 sectors after the search key.
1420  *
1421  *    But this does mean that we can't just search for
1422  *    bpos_successor(start_of_range) to get the first extent that overlaps with
1423  *    the range we want - if we're unlucky and there's an extent that ends
1424  *    exactly where we searched, then there could be a deleted key at the same
1425  *    position and we'd get that when we search instead of the preceding extent
1426  *    we needed.
1427  *
1428  *    So we've got to search for start_of_range, then after the lookup iterate
1429  *    past any extents that compare equal to the position we searched for.
1430  */
1431 __flatten
1432 void bch2_btree_node_iter_init(struct btree_node_iter *iter,
1433                                struct btree *b, struct bpos *search)
1434 {
1435         struct bkey_packed p, *packed_search = NULL;
1436         struct btree_node_iter_set *pos = iter->data;
1437         struct bkey_packed *k[MAX_BSETS];
1438         unsigned i;
1439
1440         EBUG_ON(bpos_cmp(*search, b->data->min_key) < 0);
1441         EBUG_ON(bpos_cmp(*search, b->data->max_key) > 0);
1442         bset_aux_tree_verify(b);
1443
1444         memset(iter, 0, sizeof(*iter));
1445
1446         switch (bch2_bkey_pack_pos_lossy(&p, *search, b)) {
1447         case BKEY_PACK_POS_EXACT:
1448                 packed_search = &p;
1449                 break;
1450         case BKEY_PACK_POS_SMALLER:
1451                 packed_search = NULL;
1452                 break;
1453         case BKEY_PACK_POS_FAIL:
1454                 btree_node_iter_init_pack_failed(iter, b, search);
1455                 return;
1456         }
1457
1458         for (i = 0; i < b->nsets; i++) {
1459                 k[i] = __bch2_bset_search(b, b->set + i, search, &p);
1460                 prefetch_four_cachelines(k[i]);
1461         }
1462
1463         for (i = 0; i < b->nsets; i++) {
1464                 struct bset_tree *t = b->set + i;
1465                 struct bkey_packed *end = btree_bkey_last(b, t);
1466
1467                 k[i] = bch2_bset_search_linear(b, t, search,
1468                                                packed_search, &p, k[i]);
1469                 if (k[i] != end)
1470                         *pos++ = (struct btree_node_iter_set) {
1471                                 __btree_node_key_to_offset(b, k[i]),
1472                                 __btree_node_key_to_offset(b, end)
1473                         };
1474         }
1475
1476         bch2_btree_node_iter_sort(iter, b);
1477 }
1478
1479 void bch2_btree_node_iter_init_from_start(struct btree_node_iter *iter,
1480                                           struct btree *b)
1481 {
1482         struct bset_tree *t;
1483
1484         memset(iter, 0, sizeof(*iter));
1485
1486         for_each_bset(b, t)
1487                 __bch2_btree_node_iter_push(iter, b,
1488                                            btree_bkey_first(b, t),
1489                                            btree_bkey_last(b, t));
1490         bch2_btree_node_iter_sort(iter, b);
1491 }
1492
1493 struct bkey_packed *bch2_btree_node_iter_bset_pos(struct btree_node_iter *iter,
1494                                                   struct btree *b,
1495                                                   struct bset_tree *t)
1496 {
1497         struct btree_node_iter_set *set;
1498
1499         btree_node_iter_for_each(iter, set)
1500                 if (set->end == t->end_offset)
1501                         return __btree_node_offset_to_key(b, set->k);
1502
1503         return btree_bkey_last(b, t);
1504 }
1505
1506 static inline bool btree_node_iter_sort_two(struct btree_node_iter *iter,
1507                                             struct btree *b,
1508                                             unsigned first)
1509 {
1510         bool ret;
1511
1512         if ((ret = (btree_node_iter_cmp(b,
1513                                         iter->data[first],
1514                                         iter->data[first + 1]) > 0)))
1515                 swap(iter->data[first], iter->data[first + 1]);
1516         return ret;
1517 }
1518
1519 void bch2_btree_node_iter_sort(struct btree_node_iter *iter,
1520                                struct btree *b)
1521 {
1522         /* unrolled bubble sort: */
1523
1524         if (!__btree_node_iter_set_end(iter, 2)) {
1525                 btree_node_iter_sort_two(iter, b, 0);
1526                 btree_node_iter_sort_two(iter, b, 1);
1527         }
1528
1529         if (!__btree_node_iter_set_end(iter, 1))
1530                 btree_node_iter_sort_two(iter, b, 0);
1531 }
1532
1533 void bch2_btree_node_iter_set_drop(struct btree_node_iter *iter,
1534                                    struct btree_node_iter_set *set)
1535 {
1536         struct btree_node_iter_set *last =
1537                 iter->data + ARRAY_SIZE(iter->data) - 1;
1538
1539         memmove(&set[0], &set[1], (void *) last - (void *) set);
1540         *last = (struct btree_node_iter_set) { 0, 0 };
1541 }
1542
1543 static inline void __bch2_btree_node_iter_advance(struct btree_node_iter *iter,
1544                                                   struct btree *b)
1545 {
1546         iter->data->k += __bch2_btree_node_iter_peek_all(iter, b)->u64s;
1547
1548         EBUG_ON(iter->data->k > iter->data->end);
1549
1550         while (!__btree_node_iter_set_end(iter, 0) &&
1551                !__bch2_btree_node_iter_peek_all(iter, b)->u64s)
1552                 iter->data->k++;
1553
1554         if (unlikely(__btree_node_iter_set_end(iter, 0))) {
1555                 bch2_btree_node_iter_set_drop(iter, iter->data);
1556                 return;
1557         }
1558
1559         if (__btree_node_iter_set_end(iter, 1))
1560                 return;
1561
1562         if (!btree_node_iter_sort_two(iter, b, 0))
1563                 return;
1564
1565         if (__btree_node_iter_set_end(iter, 2))
1566                 return;
1567
1568         btree_node_iter_sort_two(iter, b, 1);
1569 }
1570
1571 void bch2_btree_node_iter_advance(struct btree_node_iter *iter,
1572                                   struct btree *b)
1573 {
1574         if (bch2_expensive_debug_checks) {
1575                 bch2_btree_node_iter_verify(iter, b);
1576                 bch2_btree_node_iter_next_check(iter, b);
1577         }
1578
1579         __bch2_btree_node_iter_advance(iter, b);
1580 }
1581
1582 /*
1583  * Expensive:
1584  */
1585 struct bkey_packed *bch2_btree_node_iter_prev_all(struct btree_node_iter *iter,
1586                                                   struct btree *b)
1587 {
1588         struct bkey_packed *k, *prev = NULL;
1589         struct btree_node_iter_set *set;
1590         struct bset_tree *t;
1591         unsigned end = 0;
1592
1593         if (bch2_expensive_debug_checks)
1594                 bch2_btree_node_iter_verify(iter, b);
1595
1596         for_each_bset(b, t) {
1597                 k = bch2_bkey_prev_all(b, t,
1598                         bch2_btree_node_iter_bset_pos(iter, b, t));
1599                 if (k &&
1600                     (!prev || bkey_iter_cmp(b, k, prev) > 0)) {
1601                         prev = k;
1602                         end = t->end_offset;
1603                 }
1604         }
1605
1606         if (!prev)
1607                 return NULL;
1608
1609         /*
1610          * We're manually memmoving instead of just calling sort() to ensure the
1611          * prev we picked ends up in slot 0 - sort won't necessarily put it
1612          * there because of duplicate deleted keys:
1613          */
1614         btree_node_iter_for_each(iter, set)
1615                 if (set->end == end)
1616                         goto found;
1617
1618         BUG_ON(set != &iter->data[__btree_node_iter_used(iter)]);
1619 found:
1620         BUG_ON(set >= iter->data + ARRAY_SIZE(iter->data));
1621
1622         memmove(&iter->data[1],
1623                 &iter->data[0],
1624                 (void *) set - (void *) &iter->data[0]);
1625
1626         iter->data[0].k = __btree_node_key_to_offset(b, prev);
1627         iter->data[0].end = end;
1628
1629         if (bch2_expensive_debug_checks)
1630                 bch2_btree_node_iter_verify(iter, b);
1631         return prev;
1632 }
1633
1634 struct bkey_packed *bch2_btree_node_iter_prev(struct btree_node_iter *iter,
1635                                               struct btree *b)
1636 {
1637         struct bkey_packed *prev;
1638
1639         do {
1640                 prev = bch2_btree_node_iter_prev_all(iter, b);
1641         } while (prev && bkey_deleted(prev));
1642
1643         return prev;
1644 }
1645
1646 struct bkey_s_c bch2_btree_node_iter_peek_unpack(struct btree_node_iter *iter,
1647                                                  struct btree *b,
1648                                                  struct bkey *u)
1649 {
1650         struct bkey_packed *k = bch2_btree_node_iter_peek(iter, b);
1651
1652         return k ? bkey_disassemble(b, k, u) : bkey_s_c_null;
1653 }
1654
1655 /* Mergesort */
1656
1657 void bch2_btree_keys_stats(struct btree *b, struct bset_stats *stats)
1658 {
1659         struct bset_tree *t;
1660
1661         for_each_bset(b, t) {
1662                 enum bset_aux_tree_type type = bset_aux_tree_type(t);
1663                 size_t j;
1664
1665                 stats->sets[type].nr++;
1666                 stats->sets[type].bytes += le16_to_cpu(bset(b, t)->u64s) *
1667                         sizeof(u64);
1668
1669                 if (bset_has_ro_aux_tree(t)) {
1670                         stats->floats += t->size - 1;
1671
1672                         for (j = 1; j < t->size; j++)
1673                                 stats->failed +=
1674                                         bkey_float(b, t, j)->exponent ==
1675                                         BFLOAT_FAILED;
1676                 }
1677         }
1678 }
1679
1680 void bch2_bfloat_to_text(struct printbuf *out, struct btree *b,
1681                          struct bkey_packed *k)
1682 {
1683         struct bset_tree *t = bch2_bkey_to_bset(b, k);
1684         struct bkey uk;
1685         unsigned j, inorder;
1686
1687         if (out->pos != out->end)
1688                 *out->pos = '\0';
1689
1690         if (!bset_has_ro_aux_tree(t))
1691                 return;
1692
1693         inorder = bkey_to_cacheline(b, t, k);
1694         if (!inorder || inorder >= t->size)
1695                 return;
1696
1697         j = __inorder_to_eytzinger1(inorder, t->size, t->extra);
1698         if (k != tree_to_bkey(b, t, j))
1699                 return;
1700
1701         switch (bkey_float(b, t, j)->exponent) {
1702         case BFLOAT_FAILED:
1703                 uk = bkey_unpack_key(b, k);
1704                 pr_buf(out,
1705                        "    failed unpacked at depth %u\n"
1706                        "\t",
1707                        ilog2(j));
1708                 bch2_bpos_to_text(out, uk.p);
1709                 pr_buf(out, "\n");
1710                 break;
1711         }
1712 }